Sultone compound which is an intramolecular cyclic ester of a hydroxysulfonic acid has a —SO2—O— group as a part of the ring. Among such sultone compounds, as the one in which a plurality of rings are present in a molecule, for example, 4-hydroxy-6-oxa-7-thiabicyclo[3.2.1]octane 7,7-dioxide derivative (in the present description, this derivative is also simply referred to as “sultone derivative”) represented by the following chemical formula 3 or an enantiomer thereof is known. It should be noted that the following chemical formula 3 shows locants in a bicyclooctane ring.

As such a sultone derivative, for example, 2-hydroxy-4-oxa-5-thiatricyclo[4.2.1.03,7]nonane 5,5-dioxide derivative represented by the chemical formula 4, which has a norbornane skeleton in which Ra and Rb in chemical formula 3 are bound together to form a methylene group, is known. It should be noted that the following chemical formula 4 shows locants in a tricyclononane ring.

And as a technology to produce such 2-hydroxy-4-oxa-5-thiatricyclo[4.2.1.03,7]nonane 5,5-dioxide derivative, several methods have been proposed. For example, as shown in the following reaction scheme 1, method (1) to obtain a sultone derivative having a norbornane skeleton has been proposed. That is, Diels-Alder reaction of cyclopentadiene (CPD) and vinyl thioacetate is carried out to prepare 2-acetylthio-5-norbornene; and said norbornene derivative is oxidized using a peracid (peracetic acid) to be converted to methyl 5-norbornene-2-sulfonate, which is an ester of sulfonic acid; subsequently the double bond is epoxidized; and then methyl sulfonate group is hydrolyzed and cyclized in the presence of an acid (see Non-Patent Literature 1).

In addition, as shown in the following reaction scheme 2, method (2) to obtain a sultone derivative having a norbornane skeleton has been proposed. That is, Diels-Alder reaction of cyclopentadiene and methyl vinylsulfonate is carried out to prepare a sulfonate ester (methyl 5-norbornene-2-sulfonate); and the double bond thereof is epoxidized; subseguentlymethyl sulfonate group is hydrolyzed with an alkali; then the sulfonic acid is subjected to acid treatment to be cyclized (see Patent Literature 1).
